Mode-locked 2 μm laser with highly thulium-doped silicate fiber

Abstract

We report self-starting passively mode-locked fiber lasers with a saturable absorber mirror using a piece of 30-cm-long newly developed highly thulium (Tm)-doped silicate glass fibers. The mode-locked pulses operate at 1980 nm with duration of 1.5 ps and energy of 0.76 nJ. This newly developed Tm-doped silicate fiber exhibits a slope efficiency of 68.3%, an amplified spontaneous emission spectrum bandwidth (FWHM) of 92 nm, and a gain per unit length of greater than 2 dB/cm. To the best of our knowledge, it is the first demonstration of mode-locked 2 mum fiber laser using shorter than 1-m-long active fiber, which paves the way for the demonstration of mode-locked fiber laser at 2 mum with gigahertz fundamental repetition rate.

Efficient 287 μm fiber laser passively switched using a semiconductor saturable absorber mirror

“…Compared to Q-switched fiber lasers, mode-locked fiber lasers are particularly useful because they typically offer a higher peak power and a significantly shorter pulse width that can be used to pump optical parametric oscillators or to create a supercontinuum in the midinfrared region. In the past few years, several passively mode-locked fiber lasers emitting at 2 μm have been reported, with the best performance being achieved with thulium-doped silicate fiber that produced 1.5 ps duration pulses and 0.76 nJ pulse energies using semiconductor saturable absorber mirrors (SESAMs) [8], and with dispersion compensation, 173 fs stretched-pulses with 4 nJ pulse energy was obtained at 1.97 μm [9].Compared to Er 3 -doped ZBLAN fiber lasers, Ho 3 -doped ZBLAN fiber lasers have a longer emission peak wavelength and a higher Stokes efficiency limit as a result of the longer pump wavelength of 1150 nm. In a similar way to the transition in Er 3 -doped ZBLAN, the 5 I 6 → 5 I 7 laser transition of Ho 3 encounters a potential population bottlenecking problem because the 3.5 ms lifetime of the upper ( 5 I 6 ) laser level is shorter than the 12 ms lifetime of the lower ( 5 I 7 ) laser level and, in a parallel way to Er 3 , Ho 3 requires some engineering of the doping or laser process in order to create efficient emission.…”

“…Compared to Q-switched fiber lasers, mode-locked fiber lasers are particularly useful because they typically offer a higher peak power and a significantly shorter pulse width that can be used to pump optical parametric oscillators or to create a supercontinuum in the midinfrared region. In the past few years, several passively mode-locked fiber lasers emitting at 2 μm have been reported, with the best performance being achieved with thulium-doped silicate fiber that produced 1.5 ps duration pulses and 0.76 nJ pulse energies using semiconductor saturable absorber mirrors (SESAMs) [8], and with dispersion compensation, 173 fs stretched-pulses with 4 nJ pulse energy was obtained at 1.97 μm [9].…”

High-energy femtosecond 2-μm fiber laser

“…[9][10][11][12][13] However, the output pulse repetition rates from these oscillators were usually from a few tens of megahertz to over 100 MHz. Laser pulse trains at such high repetition rates were not convenient to achieve high pulse energy in amplification stage.…”

Midinfrared optical rogue waves in soft glass photonic crystal fiber

“…1(a), in which we show the measured loss and calculated dispersion. Now, since thulium mode-locked lasers exhibit a broad and high gain spectrum in the 1.8 to 2.1 μm wavelength regime [18], we consider pumping at the thulium wavelength λ =1930 nm, i.e., anomalous dispersion region to generate a large number of solitons as in the aforementioned studies in silica.…”